Objective: To study the effects of different marking line preparation techniques on fatigue properties of connection rod and compression fatigue properties of posterior spine internal fixation system. Methods: According to YY/T 0119.3-2014 standard, four-point flexural fatigue test was performed on the spinal connection rod. According to YY/T 0857-2011 under certain stress, systematic compression fatigue tests were carried out on laser marker line connection rod and two-color oxygen marker line connection rod. Results: Under the stress of 715MPa, the fatigue life of the self-made laser marking line connection rod (R1) and the competitive laser marking line connection rod (R2) decreased to 5% and 2%, respectively, compared with the unmarked connection rod (R0), and the fatigue strength of the laser labeled connection rod decreased by 54% from 742MPa to 342MPa compare with unmarked connection rod. The fatigue life and strength of the dual-color anodized marking line connection rod are similar to that of the unmarked connection rod. The compression fatigue strength of the dual-color anodized marking line connection rod system is 20% higher than that of the laser mark connection rod. Conclusion: Laser preparation of marker line significantly reduces the fatigue performance of the spinal rod and the compressive fatigue strength of the system. The improved dual-color anodized marking line technology has no effect on the fatigue performance，and could effectively reduce the risk of clinical fracture, providing a reference for the performance improvement and process development of the spinal bar.